2 Answers
2

I don't believe you'll find oodles of research studies in the Web Style Guide, 3rd Edition, but one of the authors, Sarah Horton, has been in the field of web wusability, so I assume at least some of their conclusions are based on research. It doesn't hurt when Edward Tufte and Donald Norman recommend the book, either.

Anyway, there are two sections online that may be of direct assistance.